The SAG nominations are considered to be one of the trustiest predictors of the Oscar best-picture contest, a significant Oscar bellwether because actors are the largest single voting bloc within the Academy of Motion Picture Arts & Sciences.

"Dallas Buyers Club," a biographical drama starring Matthew McConaughey as an electrician involved in the AIDS crisis in the 1980s and Jared Leto as a cross dresser with the disease, was something of a surprise in the category.

"It’s been a very crowded landscape and a lot of these nominations have been split," said Robbie Brenner, a producer of "Dallas Buyers Club." "Because it’s such a crowded landscape we thought we’d be recognized in certain categories— Matthew and Jared have been getting recognized a lot. But it’s a huge honor to be nominated [for cast] by the largest branch of the academy. … Anything can happen. I don’t want to get ahead of myself, but the outpouring of emotion is overwhelming.”

It was somewhat of a surprise to see two December films with large, well-regarded casts, "Saving Mr. Banks" and "The Wolf of Wall Street," omitted from the list of nominees in this category.

Last season, four of SAG's five ensemble nominees went on to earn best-picture Oscar nominations — "Argo," "Les Misérables," "Lincoln" and "Silver Linings Playbook," and both SAG and the academy chose "Argo" as the year’s top film.

Explore the red carpet as Oprah Winfrey greets spectators, the cast of Breaking Bad poses for a group photo and celebrities mingle inside the Shrine Auditorium at the Screen Actors Guild Awards. More photos